Segmented sheeting and methods of making and using same

ABSTRACT

The present invention provides a new sheeting article that may suitably include: a carrier having a first major surface and a second major surface; and a plurality of discrete segments of a sheeting (e.g., a retroreflective sheeting), wherein the sheeting has a first major viewing surface and a second major opposing surface, and the first major viewing surface of the sheeting is preferably removably attached to the second major surface of the carrier. Preferably, the first major surface of the carrier comprises a release surface, the second major opposing surface of the sheeting comprises an adhesive, the article is provided in the form of a roll, and the adhesive surface of the sheeting is adjacent the release surface of an adjacent layer of the roll. In a presently preferred embodiment the present invention provides novel easy-to-use truck conspicuity sheeting.

CROSS-REFERENCE TO CO-PENDING APPLICATION

This application is a divisional of U.S. patent application Ser. No.09/740,215, filed Dec. 18, 2000, which claims priority from ProvisionalPatent Application No. 60/173,953, filed Dec. 30, 1999, both entitledSEGMENTED SHEETING AND METHODS OF MAKING AND USING SAME.

FIELD OF THE INVENTION

This invention relates to segmented sheeting, including segmentedretroreflective-type sheeting suitable for use on a wide variety ofsubstrates, including rigid or flexible substrates.

BACKGROUND

Retroreflective sheeting has long been used to improve the night timevisibility (or “conspicuity”) of articles and vehicles. This sheeting,which was first developed by Minnesota Mining and Manufacturing Company,St. Paul, Minn. (“3M”), has greatly improved the night time visibilityof trucks and has helped prevent countless dangerous accidents.

In certain parts of the world this life-saving sheeting is now mandatedby local or national governmental bodies. Often the local governmentalbody will pass regulations that specify, for example, precisely how muchof a truck length should be delineated with the sheeting, as well asother requirements. For example, in the United States a regulationspecifies sheeting shape, mounting requirements and even provides aspacing allowance between retroreflective segments. Other jurisdictionshave different regulations. Unfortunately, however, the applier may notcorrectly apply the sheeting, for example by miscalculating the spacingrequirements for their particular jurisdiction. In such cases thedelineation will have to be corrected, often at considerable cost.

Also, certain types of vehicles have siding that makes it difficult touse the most cost-efficient sheeting. For example, certain canvas-sidedtrucks would benefit if the generally more common and less costly“rigid-type” of retroreflective sheeting could be used. Unfortunately,however, the flexible nature of the canvas siding does not work wellwith the more rigid-types of sheeting and the user is left to use a morecostly “flexible-type” of sheeting.

From the foregoing, it will be appreciated that what is needed in theart is improved sheeting for article and vehicle conspicuity programs.Such sheeting and methods for preparing and using the same are disclosedand claimed herein.

SUMMARY

In one embodiment, the present invention provides a new sheeting articlethat comprises a carrier having a first major surface and a second majorsurface; and a plurality of discrete segments of a sheeting (e.g., aretroreflective sheeting), wherein the sheeting has a first majorviewing surface and a second major opposing surface, and the first majorviewing surface of the sheeting is attached, preferably “removably”attached, to the second major surface of the carrier.

In another embodiment, the present invention provides a new sheetingarticle that comprises a carrier having a first major surface and asecond major surface; a plurality of discrete segments of a firstretroreflective sheeting; and a plurality of discrete segments of asecond retroreflective sheeting, wherein the sheeting has a first majorviewing surface and a second major opposing surface, and the first majorviewing surface of the sheeting is attached to the second major surfaceof the carrier. In a preferred embodiment, the first retroreflectivesheeting segments are spaced along a major length of the article and atleast a portion of the second retroreflective sheeting segments areinterspersed therebetween.

In yet another embodiment, the present invention provides a new sheetingarticle that comprises a carrier having a first major surface and asecond major adhesive surface; and a plurality of discrete segments ofsheeting (e.g., a retroreflective sheeting), wherein the sheeting has afirst major viewing surface, a second major opposing surface, and aperiphery, the first major viewing surface of the sheeting is attachedto the second major adhesive surface of the carrier, and the carrierextends beyond the periphery of the discrete segments of retroreflectivesheeting.

In a presently preferred embodiment the present invention providesnovel, easy-to-use truck conspicuity sheeting.

The present invention also provides novel methods of making and usingthe above articles.

One such preferred method includes the steps of providing an elongatestrip of a carrier having a first major surface and a second majorsurface; providing an elongate strip of a retroreflective sheeting,wherein the sheeting has a first major viewing surface and a secondmajor opposing surface (preferably an adhesive surface); cutting theelongate strip of retroreflective sheeting into smaller discretesegments; and attaching, preferably “removably” attaching, the firstmajor viewing surface of the sheeting to the second major surface of thecarrier.

Another method includes the steps of providing an elongate strip of aretroreflective sheeting on a release liner, wherein the sheeting has afirst major viewing surface and a second major opposing adhesive surfaceprotected by the liner; cutting the elongate strip of retroreflectivesheeting into smaller discrete segments on the liner; stretching theliner in at least one direction to separate segments; and attaching,preferably “removably” attaching, the first major viewing surface of thesheeting to a second major surface of an elongate strip of a carrierhaving a first major surface and a second major surface.

Another method includes the steps of providing an elongate strip of aretroreflective sheeting on a release liner, wherein the sheeting has afirst major viewing surface and a second major opposing adhesive surfaceprotected by the liner; cutting the elongate strip of retroreflectivesheeting into smaller discrete segments on the liner; removing selectedportions of the sheeting to separate the remaining segments; andattaching the first major viewing surface of the sheeting to the secondmajor surface of an elongate strip of a carrier having a first majorsurface and a second major surface.

One method of using the above articles includes the steps of providingan elongate strip of a conspicuity article having (i) a carrier with afirst major surface and a second major surface and (ii) a plurality ofdiscrete segments of a retroreflective sheeting having a first majorviewing surface and a second major opposing adhesive surface protectedby a release surface, wherein the first major viewing surface of thesheeting is attached, preferably “removably” attached, to the secondmajor surface of the carrier; exposing the second major opposingadhesive surface of the sheeting; and applying the adhesive surface ofthe sheeting to a surface of a vehicle to thereby adhere the sheeting tothe vehicle. In a preferred embodiment the method includes an additionalstep of removing the carrier from the applied article to thereby exposethe first major viewing surface of the sheeting

In yet another embodiment the method further comprises partially tearingthe carrier along a plurality of discontinuities provided therein duringthe step of applying the adhesive surface of the sheeting to a flexiblesubstrate on the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further explained with reference to theappended Figures, wherein like structure is referred to by like numeralsthroughout the several views.

FIG. 1 a shows a top view of one embodiment of the segmented sheeting ofthe present invention; FIG. 1 b is a cross-sectional view of thesegmented sheeting of FIG. 1 a, taken along line 1 b—1 b.

FIGS. 2 a and 2 b show alternative cross-sectional views of thesegmented sheeting of the present invention and further illustratealternative liners for use therewith.

FIGS. 3 a–3 g show top views of alternative segmented sheeting of thepresent invention, wherein the sheeting portion comprises an exemplaryvariety of shapes, patterns and/or spacing therebetween.

FIG. 4 shows a top view of an alternative embodiment of the segmentedsheeting of the present invention having two carrier strips rather thana single carrier.

FIG. 5 a shows a top view of another embodiment of the segmentedsheeting of the present invention wherein the carrier is segmented; FIG.5 b is a cross-sectional view of the segmented sheeting of FIG. 5 a,taken along line 5 b—5 b.

FIG. 6 shows a top view of another embodiment of the segmented sheetingof the present invention wherein the sheeting portion is furthersegmented along the lengthwise axis.

FIG. 7 a shows a top view of another embodiment of the segmentedsheeting of the present invention wherein the carrier extends beyond theedges of the sheeting segments; FIG. 7 b is a cross-sectional view ofthe segmented sheeting of FIG. 7 a, taken along line 7 b—7 b.

FIGS. 8 a–8 g schematically illustrate alternative manufacturingprocesses of the present invention.

FIG. 9 is a graph illustrating correlation between predictive data andmeasured data for segmented sheeting in a wrinkle failure mode.

FIGS. 10–13 are diagrammatic views illustrating various failure modes.

These figures, which are idealized, are not to scale and are intended tobe merely illustrative and non-limiting.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention provides retroreflective sheeting articles (andmethods of making and using such articles) that solve one or more of theunmet needs noted above.

In one embodiment, the present invention relates to retroreflectivetruck conspicuity sheeting having a carrier. The carrier preferablyfacilitates the placement and/or orientation of retroreflective segmentson a substrate. For example, the articles of the present invention maybe easily adapted for use on flexible substrates such as canvas trucksides. As used herein, retroreflectivity includes any article thatprovides a reflected beam back toward the source for angles of incidencethat are not normal to a viewing surface of the article. Thus, aretroreflective article can be any suitable type of article including,for example, prismatic, encapsulated beads, embedded beads, and enclosedtype retroreflective articles.

FIG. 1 a shows a top view of one embodiment of a segmented sheetingarticle 10 of the present invention. FIG. 1 b is a cross-sectional viewof the segmented sheeting of FIG. 1 a, taken along line 1 b—1 b. Asshown, segmented sheeting article 10 includes a carrier 14 having afirst major surface 16 and a second major surface 18. Sheeting article10 further includes a plurality of sheeting segments, typicallyretroreflective sheeting segments 12 (12 a, 12 b, 12 c) or “pieces”attached to the carrier. Sheeting segments 12 (12 a, 12 b, 12 c)typically comprise a sheeting viewing surface 20 (typically aretroreflective backing) and an adhesive layer 22. Sheeting segments 12are discrete and may optionally be separated from adjacent segments by agap 13. Segments 12 a, 12 b, 12 c, etc. may be the same or different.For example, 12 a and 12 c could be of a first type and 12 b of a secondtype of sheeting. This construction may be used to provide an articlewith, for example, alternating red and white colors.

In one embodiment, first major surface 16 comprises an optional releasecoating. Suitable such release coatings include low adhesion backsize(LABs) such as are common in the pressure sensitive adhesive tapeindustry. When the carrier 14 comprises an optional release surface orcoating, the sheeting article 10 may be conveniently provided in theform of a pad or roll and adhesive layer 22 placed in contact with theoptional release surface or coating of an adjacent carrier, e.g., whenadjacent layers of a roll are placed in contact.

FIGS. 2 a and 2 b show alternative cross-sectional views of thesegmented sheeting of the present invention and further illustratealternative liners for use therewith. In FIG. 2 a, segmented sheeting 30is provided with a separate “continuous” release liner 24 a. Thefunction of the release liner is to protect the adhesive layer 22 priorto its use against a substrate. In use, release liner 24 a would beremoved (e.g., peeled off) to expose adhesive 22 prior to application ofthe article to a substrate. In FIG. 2 b, segmented sheeting 32 isprovided with a separate “segmented” release liner 24 b. As describedabove, the liner pieces would be removed prior to application of thearticle to a substrate.

FIGS. 3 a–3 g show top views of alternative segmented sheeting of thepresent invention, wherein the sheeting portion comprises an exemplaryvariety of shapes, patterns and/or spacing therebetween.

The article of FIG. 3 a is similar to that shown in FIG. 1 a, however,the gap 13 between adjacent segments 12 is smaller. It is within thescope of the present invention to have no gap between adjacent segments.However, for use on flexible substrates, e.g., canvas truck sides, thepresence of a gap is preferred. Such gaps allow greater flexibility inthe resultant truck side, particularly when the sheeting is of a morerigid-type of sheeting. As will be illustrated in greater detail later,some of the embodiments that employ gaps are utilized without generatingwaste, known as material weed.

The article of FIG. 3 b illustrates segments 12 having “diamond” shapes.One method of producing such shapes is to cut square or rectangularshapes from a strip (thereby not wasting any sheeting) and rotate thesegments 45 degrees when attaching them to the carrier.

The article of FIG. 3 c illustrates segments 12 having “circular”shapes.

The article of FIG. 3 d illustrates segments 12 having “irregular”shapes such as might constitute a logo or message.

The article of FIG. 3 e illustrates an article 34 e having a largenumber of small segments 12 having “rectangular” shapes. One method ofproducing such an article is to (1) “kiss” cut (a “kiss” cut is apartial cut that does not extend through all layers) a retroreflectivestrip on a stretchable liner into a pattern of small rectangles, (2)stretch the strip (either lengthwise or widthwise or both) to separatethe segments, and then (3) attach the separated segments to a carrier.This method can be utilized with any other “packable” pattern, i.e., anyother pattern than packs together and can be cut from a sheet withminimal or no waste.

FIG. 3 f illustrates an article 34 f having a plurality of discretesegments 12 which combined reveal a message or graphic.

The article of FIG. 3 g illustrates segments 12 having “chevron” shapes.

FIG. 4 shows a top view of an alternative embodiment of a segmentedsheeting article 36 of the present invention. As shown, segmentedsheeting article 36 includes two carriers 14 (14 a, 14 b) along eachedge of the article. Sheeting article 36 further includes a plurality ofsheeting segments 12 or “pieces” (typically retroreflective sheetingsegments) attached to the carriers.

FIG. 5 a shows a top view of another embodiment of a segmented sheetingarticle 37 of the present invention. FIG. 5 b is a cross-sectional viewof the segmented sheeting of FIG. 5 a, taken along line 5 b—5 b. Asshown, segmented sheeting article 37 includes a plurality of segmentedcarrier pieces 14. Sheeting article 37 further includes a plurality ofsheeting segments 12 (typically retroreflective sheeting segments)attached to the carrier. If desired, the carrier may be permanentlyattached to the sheeting segments, e.g., by use of a permanent adhesive,bonding, sonic welding, riveting, sewing, or other methods. The carrierpieces in such cases remain attached to the article after it has beenapplied to a substrate and are not subsequently removed. Sheetingsegments 12 typically comprise a retroreflective surface 20 and anadhesive layer 22. Sheeting segments 12 are discrete and may optionallyand preferably be separated from adjacent segments by a gap 13. Ifdesired, an optional release liner 24 a (or a segmented release liner,not shown) may be used.

FIG. 6 shows a top view of another embodiment of the segmented sheeting38 of the present invention, wherein the sheeting portion 12 is furthersegmented into three smaller pieces (12 a, 12 b, and 12 c). Theembodiments shown in FIG. 6 illustrate an article where separationsexist between adjacent segments 12, however, it is within the scope ofthis invention that smaller gaps or no gaps be present therebetween.Also, it is within the scope of this invention that gaps exist betweenpieces 12 a, 12 b and/or 12 c.

One feature of the sheeting of FIG. 6 is that increased flexibility canbe achieved by providing cut lines 11. In most preferred embodiments ofthe present invention, the cut lines 11 do not substantially adverselyaffect the performance properties of the sheeting. For example, whensegment 12 comprises a sealed prismatic or beaded retroreflectivesheeting, it may be preferable to seal the edges of the segment piecesto avoid subsequent loss of performance of the sheeting. Such edgesealing may not be necessary in the case of retroreflective sheetingthat utilizes, a reflective coating layer rather than an air interface.

FIG. 7 a shows a top view of another embodiment of the segmentedsheeting 39 of the present invention wherein the carrier 15 extendsbeyond the edges of the sheeting portion. FIG. 7 b is a cross-sectionalview of the segmented sheeting of FIG. 7 a, taken along line 7 b—7 b. Inthis embodiment, carrier 15 is shown having a backing layer 17 and anadhesive layer 19. The extension of carrier 15 beyond the edges of thesheeting portion 12 allows the carrier to be used, if desired, to securethe article to a substrate or to seal the sheeting from the surroundingenvironment. Consequently, in this embodiment there is no requirementthat portion 12 comprise its own adhesive layer, though such a layer maybe utilized if desired.

FIG. 8 a schematically illustrates one manufacturing process 40 of thepresent invention. In this process a roll 42 of sheeting 44 (typicallyretroreflective sheeting) (shown on an optional release liner) isunwound and passed through a cutting apparatus 48 to form a segment 50of sheeting. The segment 50 is then positioned against a carrier 52 andattached thereto. In preferred embodiments of this process, the carriercomprises an adhesive surface 56 that secures the segment thereto. Inpreferred embodiments the segments (50, 50 b, 50 c, etc.) are positionedalong the carrier with gaps 58 therebetween. In most preferredembodiments, the carrier 52 with attached segments 50 is then wound upto form a roll 60 of segmented sheeting. If desired, an optional liner(not shown) may be used to cover and protect the optional adhesivesurface of the segment. Alternatively, the carrier 52 may comprise arelease surface 54 and itself function as a liner.

FIG. 8 b schematically illustrates another manufacturing process 70 ofthe present invention. For simplicity, illustration of removal of therelease liners is omitted in FIG. 8 b, however such steps are indeedperformed. In this process a first roll 72 a of sheeting 74 a (typicallyretroreflective sheeting) is unwound and passed through a cuttingapparatus 78 a to form a segment of sheeting 80 a. The segment 80 a isthen positioned against a carrier 82 and attached thereto. A second roll72 b of sheeting 74 b is unwound and passed through a second cuttingapparatus 78 b to form a segment of sheeting 80 b. The segment 80 b isthen positioned against a carrier 82 and attached thereto, typicallybetween segments of the first sheeting 74 a. In preferred embodimentsthe segments are positioned along the carrier with gaps therebetween.The two sheetings (74 a, 74 b) may be the same or different. In oneembodiment the two sheetings have different retroreflective properties(e.g., different optical properties) or different colors and the twosheetings are alternated along the carrier. In most preferredembodiments the carrier 82 with attached segments 80 a and 80 b is thenwound up to form a roll 90 of segmented sheeting. If desired, anoptional liner (not shown) may be used to cover and protect the optionaladhesive surface of the segment. Alternatively, the carrier 82 maycomprise a release surface 84 and itself function as a liner.

FIG. 8 c schematically illustrates another manufacturing process 90 ofthe present invention. In this embodiment sheeting 91 is provided in theform of a plurality of cut and sealed retroreflective segments withadhesive and an adhesive carrier. Sheeting 91 is provided to drive rolls92 a and 92 b, which draw sheeting 91 therethrough. At point 94, theadhesive carrier is stripped from sheeting 91 and spooled upon roll 96.Then, an adhesive liner 98 with release surface 100 is brought intocontact with sheeting 91 at rollers 102 a and 102 b. An elongate carrier104, having adhesive surface 106, is brought into contact with sheeting91 at rollers 102 a and 102 b. The resulting product 108 includes anelongate carrier, a plurality of sheeting segments and an adhesiveliner. As will be appreciated by those skilled in the art, the relativespacing between the various segments can be accurately controlled byvarying the rotational speed of rollers 102 a and 102 b with respect torollers 92 a and 92 b.

FIG. 8 d schematically illustrates another manufacturing process 110 ofthe present invention. This embodiment is similar to that illustrated inFIG. 8 c and like elements are numbered similarly. Sheeting 91 isprovided in the form of a plurality of cut and sealed retroreflectivesegments disposed upon adhesive and an adhesive carrier. Sheeting 91 isprovided to drive rolls 92 a and 92 b, which draw sheeting 91therethrough. At point 94, the adhesive carrier is stripped fromsheeting 91 and spooled upon roll 96. Individual sheeting segments arethen provided to one of a plurality of lines 111, 113 based uponselective operation of actuator 112. Although a pair of lines 111, 113are illustrated, those skilled in the art will appreciate that anysuitable number of lines may be used. In each line, an adhesive liner 98a, 98 b with release surface 100 a, 100 b is brought into contact withsheeting 91 at rollers 102 a, 102 b and 114 a, 114 b. Elongate carrier104 a, 104 b, having adhesive surface 106 a, 106 b is brought intocontact with sheeting 91. The resulting products 108 a and 108 b includean elongate carrier, a plurality of sheeting segments and an adhesiveliner. This embodiment provides a pair of finished product rolls fromthe same stock of segmented sheeting, which finished rolls may have thesame spacing between adjacent segments, or different spacing dependingupon the relative speeds of rollers 102 a, 102 b, 114 a, and 114 b.

FIG. 8 e schematically illustrates another manufacturing process 120 ofthe present invention. In this embodiment sheeting segments 122 areprovided to rollers 124 a and 124 b along with carrier 126 (withadhesive surface 127) and adhesive liner 128 (with release surface 129).The various components are pinched together by rollers 124 a and 124 bto form intermediate product 130. At rollers 132 a and 132 b, a numberof discontinuities are generated in the elongate carrier 126. Suchdiscontinuities may take any suitable shape, but are preferably slots.One method of generating slots in carrier 126 includes using a roller132 b that includes a number of cutters 136. This is preferable becausethe function of a roller opposing roller 132 a and the function ofcutting slots are combined. However, those skilled in the art willappreciate that the various functions can separated as desired. FIG. 8 gis a perspective view of the preferred roller 132 b illustrating cutters136. FIG. 8 f is a top view of finished product 138 illustratingdiscontinuities 140 extending across the width of product 138 betweensegments 122.

Suitable and preferred materials and methods of assembly and use of thearticles of the present invention are as follows.

Suitable articles of the present invention comprise a carrier having afirst major surface and a second major surface. Preferred carriers aregenerally elongated strips. More preferred carriers for use in thepresent invention are typically provided in the form of a roll.

Suitable carriers include film and sheet backing materials. Aparticularly preferred carrier includes a polymeric film backingmaterial. For example, suitable carriers include those polymeric backingfilms that have the strength to support the attached sheeting segmentsduring the manufacturing process and/or during subsequent application ofthe article to a substrate. For certain embodiments (e.g., where thecarrier is designed to be removed after application of the sheeting to asubstrate), the carrier preferably has a sufficient tensile strength topermit the carrier to be easily peeled away from the attached sheeting.Alternatively, the carrier may be made of a suitable material that maybe removed from the sheeting (e.g., after application of the sheeting toa substrate) by dissolving the carrier away.

In more preferred embodiments, the carrier has an adhesive surface,e.g., for attaching the sheeting segments to the carrier. Typically thisadhesive will be a pressure sensitive adhesive (“PSA”), however, othersuitable types of adhesives (e.g., non-tacky adhesives such as aredisclosed in U.S. Pat. Nos. 6,004,670; 5,912,059; 5,908,695; and5,888,335) may be used if desired.

Suitable PSAs include those that provide the requisite adhesion to thesheeting segments. Preferably the PSA provides suitable adhesivestrength to support the sheeting segments during the manufacturingprocess and/or during the application of the sheeting segments to asubstrate. Suitable PSAs include those described, for example, in U.S.Pat. Nos. 5,861,211; 5,905,099; 5,820,988; 5,804,610; 5,639,530;5,584,962; 5,580,417; 5,453,320; 5,391,015; 5,334,686; 4,985,488;4,946,742; and 4,248,748. In cases where the carrier is designed toremain attached to the applied article, the PSA preferably is selectedwith long term durability in mind. In cases where the carrier isintended to be removed (e.g., peeled off) after the article is appliedto the substrate the choice of adhesive or the amount of adhesive used(e.g., coating weight, coating pattern or coating texture) shouldpreferably be adjusted so that the carrier can be easily peeled off. Inother words, preferably the force of adhesion to the sheeting segmentand/or to the substrate is not such that the removal of the carriercauses either the sheeting segments to release from the substrate ormakes removal of the carrier from the substrate too difficult.

Other suitable PSAs, e.g., for use when producing an article having aremovable carrier, include water dispersible PSAs such as are describedin U.S. Pat. Nos. 3,865,770; 4,413,080; 4,569,960; 5,125,995; 5,270,111;5,380,779, 5,397,614 and 5,460,880. This type of adhesive isparticularly suited for use with water dissolving carrier backings, aspreviously described. In cases where both the carrier backing andadhesive layer are dissolvable, e.g., with water, the carrier can besimply washed off from the substrate without the need to peel thecarrier off.

It is within the scope of the present invention to use alternativeattachment means. Suitable other means include “non-tacky adhesivesystems” (such as are disclosed in the aforementioned patents), and/orthe direct lamination to suitable polymer surfaces. With properselection of the non-tacky adhesive system or lamination method thecarrier to sheeting adhesion force may be suitably adjusted.

It is also within the scope of the present invention to use alternative“permanent” attachment means. Suitable “permanent” types of attachmentinclude sonic welding methods, lamination methods (e.g., heatlamination), etc. For example, the carrier may be sonically welded tothe sheeting using lines, spots, etc. It is recognized that the“permanence” of the attachment, however, may be varied, for example, byvarying the number or size of the welds.

Suitable carriers, in addition to positioning and supporting a pluralityof sheeting segments, are preferably also somewhat extensible. As hasbeen previously described, the articles of the present inventiontypically comprise a carrier and a plurality of sheeting segmentsattached thereto. In some cases the sheeting segments may not themselvesbe very extensible. Segmented articles having low extensible sheetingsegments may be effectively extensible primarily or only at the gapsbetween the segments. Consequently, preferred carriers are extensibleand allow the article to be positioned along an irregular surface, e.g.,bent around obstacles, bent around curves and/or corners, stretched overrivets, stretched over pre-existing fold lines in a flexible substrate,etc. Most preferably the carrier maintains its original shape (e.g., astraight lengthwise shape) during application of the article along astraight substrate, yet can be extensibly stretched by the applier whendesired, e.g., to go around a wheel-well of a vehicle. In someembodiments, however, very extensible carriers are used, such as that ofExample 1, Run 9 set forth below, where the degree of carrierextensibility facilitates “steering” or otherwise directing applicationof the retroreflective segments in non-linear applications. For example,if the segments are to be applied in an “S” pattern, the extensiblecarrier can be stretched and turned during application in order togenerate the appropriate curves for the pattern.

In alternative embodiments, e.g., where the carrier is designed toremain attached to the article, the carrier is preferably constructedusing suitable ultraviolet (“UV”) light absorbers and/or otheradjuvants. Preferred adjuvants help provide long-term durability to thecarrier and/or underlying article. The carrier may also provide one ormore feature to the article such as scratch resistance, dew resistance,mold and organism resistance, dirt resistance, graffiti resistance, etc.For example, the carrier may be constructed using Scotchlite PremiumProtective Overlay Film, which comprises an ethylene tetrafluoroethylenefilm with an acrylate adhesive layer and which provides several of theabove mentioned features. Carriers such as Prespace Tape sold by 3Munder the trade designation SCPS-2, and Premask Tape sold by 3M underthe trade designation SCPM-3 can also be used.

In more preferred embodiments, the carrier has a release surface. Therelease surface facilitates the unwinding of the carrier when it isprovided in the form of a roll and/or facilitates the unwinding of thearticle (without unintended detachment of sheeting segments) when thearticle is in the form of a roll.

Suitable release surfaces include low adhesion backsize (“LAB”) coatingssuch as are known in the adhesive tape arts. Suitable LABs includetypical silicone release coating materials such as are used on the linercomponent provided with a graphic article commercially available from 3Munder the trade designation “3M Scotchlite Premium Protective OverlayFilm Series 1160.” Suitable LABs are also disclosed in U.S. Pat. Nos.5,817,376; 5,962,546; 5,858,545.

Suitable articles of the present invention comprise a plurality ofdiscrete segments of a sheeting, e.g., retroreflective, reflective ornon-reflective sheeting. Suitable such sheeting has a first majorviewing surface and a second major opposing surface. In preferredembodiments the first major viewing surface of the sheeting is removablyattached to the second major surface of the carrier.

Suitable retroreflective sheeting includes “beaded-type” retroreflectivesheeting (e.g., exposed lens, enclosed lens, and encapsulated lenssheeting) and “prismatic-type” or “cube-corner-type” sheeting (e.g.,encapsulated prismatic-type and metalized prismatic sheeting). Suitabletypes of retroreflective sheeting are described in ASTM D 4956-94entitled “Standard Specification for Retroreflective Sheeting forTraffic Control”. Brightness or retroreflectivity of the sheeting may beexpressed as the Coefficient of Retroreflection, R_(a). This is measuredin units of candelas/lux/square meter and is determined using ASTM E810-94.

The retroreflective sheeting may be a flexible-type sheeting or a morerigid-type sheeting. An advantage of the articles of the presentinvention is that rigid-types of sheeting or less extensible types ofsheeting can be used, even on flexible substrates such as are found oncanvas-sided trucks.

Illustrative examples of exposed lens retroreflective sheeting aredisclosed in U.S. Pat. Nos. 2,326,634; 2,354,018; 2,354,048; 2,354,049;2,379,702; and 2,379,741. Illustrative examples of enclosed lensretroreflective sheeting are disclosed in U.S. Pat. Nos. 2,407,680;3,551,025; 3,795,435; 4,530,859; 4,588,258; 4,664,966; 4,775,219;4,950,525; 5,064,272; and 5,882,771. Illustrative examples ofencapsulated lens retroreflective sheeting are disclosed in U.S. Pat.Nos. 3,190,178; 4,025,159; 4,663,213; 5,069,964; 5,605,761; 5,714,223;5,812,316; and 5,784,198. Illustrative examples of encapsulatedprismatic-type retroreflective sheeting are disclosed in U.S. Pat. Nos.5,138,488; 5,450,235; 5,614,286; 5,706,132; 5,714,223; and 5,754,338.Illustrative examples of other prismatic-type retroreflective sheetingare disclosed in U.S. Pat. No. 5,914,812; 5,491,586; 5,642,222;5,376,431.

When encapsulated-type sheeting is used it is preferred that thesegments be formed in such a way that the edges of the segments aresealed to prevent moisture and/or dirt contamination. This can be donein a variety of ways as is well appreciated in the art. For example,when such sheeting is manufactured a seal-line can be provided in thesheeting and the segments may be cut from the sheeting by cuttingthrough the seal-lines. Also, the sheeting can be cut and the edgessealed in a later step by, for example, using a sealing material alongthe unsealed edges. Also alternatively, in certain embodiments of thepresent invention, the carrier itself may extend beyond the edge of thesheeting and be used to form sealed pockets (i.e., the carrier and thesubstrate together form a pocket), with the sheeting being containedtherein.

Preferred sheeting for use in the present invention comprises anadhesive surface. The choice of adhesive is dictated by many factors,for example, the type of substrate to which the sheeting is to beadhered. In preferred embodiments the adhesive will be a PSA. Mostpreferably the adhesive provides durability for the intended life of thesheeting article. In addition to the adhesives disclosed in theaforementioned patents, some representative patents related to PSAsinclude: U.S. Pat. Nos. 5,861,211; 5,905,099; 5,820,988; 5,804,610;5,639,530; 5,584,962; 5,580,417; 5,453,320; 5,391,015; 5,334,686;4,985,488; 4,946,742; and 4,248,748.

Suitable retroreflective sheeting can be provided in a variety ofcolors, shapes, and/or have a variety of optical properties. In certainpreferred embodiments of the present invention sheeting segments of morethan one color or more than one optical property may be employed. Forexample, a carrier might comprise a plurality of “red” retroreflectivesheeting segments spaced there along and with large gaps between the redsheeting segments. The large gaps, or portions of the large gaps, canthen be filled with a different (e.g., a “white”) retroreflectivesheeting. The resultant article will comprise, for example, alternatingred and white sheeting. Alternatively, segments having more than oneretroreflective optical property (e.g., narrower or broader entranceand/or observation angularity) may be used along a carrier. For example,alternating segments that exhibit a particular preferred entranceangularity direction or plane (e.g., left, right, up, down, horizontal,vertical) and fluorescent properties may be positioned along the carrierto create a conspicuity article.

In preferred embodiments of the present invention the selection ofadhesives and release surfaces are chosen to facilitate manufacture,handling and/or use of the article. For example, in certain embodimentsthe sheeting segments are designed to be removably attached to thecarrier. In these embodiments the term “removably attached” means thatthe carrier is designed to be temporarily attached to the sheeting. Forexample, the sheeting segments are preferably well enough attached tothe carrier that they remain attached during manufacture and handling ofthe article. However, in these embodiments the carrier is preferablydesigned to be peeled off of the sheeting without damaging the sheetingor causing the sheeting segments to be prematurely removed from thesubstrate to which they are applied. Also in this embodiment, preferablythe carrier is designed to easily be peeled off of the substrate towhich the article is applied. In more preferred embodiments (e.g., wherethe carrier and the sheeting each comprise a PSA and the carriercomprises a release surface), the PSAs are chosen such that the carrierand sheeting can be peeled off of the underlying layers of the rollwithout causing sheeting segments to separate from the adhesive surfaceof the carrier, and when the sheeting and carrier are applied to asubstrate the adhesion of the sheeting to the substrate is high enoughthat the carrier can be peeled away from the sheeting without causingsegments of the sheeting to separate from the substrate.

It is contemplated that this effect can be achieved in a variety ofways. For example, the selection and use of suitable low adhesioncoatings (e.g., on the carrier or release liner or optionally on theviewing surface of the sheeting) can help adjust the adhesionproperties. Also, the choice of adhesive, coating weight of theadhesive, or texture of the adhesive can be chosen to accomplish thisend.

It is contemplated that articles of the present invention may beprovided in a variety of forms. For example, for truck conspicuitypurposes the articles conveniently may be provided as long strips whichmay be fan folded, stacked (e.g., in a pad), in roll form or packaged insome other manner. A preferred form is as a roll.

Suitable articles may include liners to protect the surfaces of thearticle. For example, a release liner may be used to protect an adhesivesurface (e.g., a tacky adhesive surface) prior to its applicationagainst a substrate. Alternatively, the article itself may comprise asuitable release surface (e.g., on the carrier) such that when thearticle is provided in a pad or roll form the adhesive surfaces can beprotected. This embodiment has a couple of advantages. First, it avoidsthe need for a separate liner, thus saving cost. Second, the userdoesn't have to handle a separate liner or provide for its disposal.

The features of the present invention are useful in the manufacture oruse of a variety, of articles. One such preferred article is a vehicleconspicuity article (e.g., an article for use on a car, truck, boat,railroad car, plane, trailer, ground handling equipment, farm equipment,bicycle, motorcycle, etc.). Other uses include barrel wrap conspicuityarticles (e.g., for use on barrels), traffic cone and tube conspicuityarticles, barrier conspicuity articles (such as for use of roadways),flexible signage, helmets (e.g., bicycle helmets), backpacks, andapparel (e.g., safety vests and jackets).

For use as a vehicle conspicuity article the article is preferablyprovided in a form acceptable to the respective governing body. Oneregulation of particular note is the United Nations “AgreementConcerning The Adoption Of Uniform Technical Prescriptions For WheeledVehicles, Equipment And Parts Which Can Be Fitted And/Or Used On WheeledVehicles And The Conditions For Reciprocal Recognition Of ApprovalsGranted On The Basis Of These Prescriptions (Rev. 2/Add. 103; E/ECE/324;E/ECE/Trans/505)”. This document provides, among other things, forvarious specifications for conspicuity sheeting. Preferred sheeting ofthe present invention meets or exceeds these specifications.

Additional embodiments of the present invention were realized upondetailed analysis of common failures of retroreflective sheeting adheredto a flexible substrate such as canvas. The purpose of the analysis wasto determine advantageous properties for mounting retroreflectivesheeting to a canvas substrate. As described above, canvas flexes easilyespecially when used as a side of a truck. When flexed, the canvasbends. If the position of the segment is such that free bending of thecanvas at the gap between segments does not occur then theretroreflective sheeting disposed thereon is forced to react.Retroreflective sheetings are typically laminate structures. Theretroreflective sheeting-laminate will react based upon its material(s),layer thickness(es), position and distribution of materials within thelaminate, and the ability of the adhesive to withstand applied loads. Ingeneral, the retroreflective laminate can fail in any of four modes.

The first mode of failure is illustrated in FIGS. 10A and 10B, andoccurs when the bending of the canvas puts the first major surface ofthe segment in tension and initiates a crack in the first major surface.In FIG. 10A, the substrate 200 and segment 202 are flat. In FIG. 10B,substrate 200 has been bent, and cracks 204 in segment 202 are formed.Such cracking can occur after many flexes or as a brittle failure on asingle flex. Proper choice of material flexibility for the intended useenvironment can avoid this failure mode.

The second failure mode is illustrated in FIG. 11 and occurs when anedge, such as edge 206 of segment 202 lifts, or otherwise begins to peelback. This failure mode generally occurs when segment edge 206 islocated upon a portion of substrate 200 that is bent. Segment 202 reactsapplying a bending moment on the adhesive. One of the manners in whichthis failure mode is remedied is by choosing an adhesive that isspecially adapted for the substrate. One adhesive that worksparticularly well with canvas is a PSA as described in U.S. Pat. No.5,861,211. Although this adhesive is particularly suited for canvas,those skilled in the art will appreciate that any suitable adhesive canbe used. However, even the best adhesive can only withstand a finitebending moment from a before it fails. Thus a second manner in whichthis failure mode is remedied is by choosing laminates with smallbending rigidities. It is instructive to consider a simple, idealizedcase where the edge is bent to a constant curvature. The moment appliedto the adhesive is approximated to be proportional to the rigidity ofsegment 202 and inversely proportional to the radius of the circle. Forexample empirical evidence indicates that the PSA as described in U.S.Pat. No. 5,861,211 at 70 degrees Celsius can withstand a bending moment,M, from a segment up to about 6×10⁻³N*m before it de-bonds from a testcanvas, Verseidag Indutex/German, type Duraskin 12 B129835. 3M #981retroreflective sheeting, a typical rigid, sealed “prismatic-type”sheeting has a bending rigidity, D, of about 6×10⁻⁵N*m². Thus the radiusto which the a segment of 3M #981 and the PSA as described in U.S. Pat.No. 5,861,211 will withstand bending without edge-lift at 70 degreesCelsius isD/M=6×10⁻⁵N*m²/6×10⁻³N*m=1×10⁻²m=10 mm.Adhesives that can withstand higher moments before failure and/or use ofless rigid segments would allow said segment to bend to smaller radiibefore failing.

The third mode of failure is illustrated in FIG. 12 and occurs when ajet of high pressure, fast flowing water 208 impinges upon any edge ofsegment 202. It is believed that this failure mode is also related tothe adhesive. This type of failure is believed not related to mechanicalreactions, laminate properties or any width-length combination thatwould be unique to segments describe here. Segments from thin andflexible to thick and stiff adhered to canvas with an adhesiveparticularly suited for canvas seem not to fail when exposure to a highpressure jet of water.

The fourth failure mode is illustrated in FIGS. 13A and 13B. Thisfailure mode occurs when the retroreflective segment 202 is placed incompression, for example when the substrate 200 (such as canvas) towhich segment 202 adheres is flexed so as to bend segment 202 around aninside arc. In this situation, a portion of the retroreflective overlaysegment 202 may buckle as illustrated at wrinkle 210. The buckledportion 210 then lifts from substrate 200. A number of segments 202 madeof five distinct laminates, each laminate tested with widths between 13mm and 50 mm and lengths between 13 mm and 150 mm, were adhered to thetest canvas Duraskin 12 B129835 and the constructions bent over variousinside radii to determine the minimum length that avoided wrinkling.Material properties of and the five laminates relevant to the discussionthat follows are listed in Tables 1.

TABLE 1a Material Modulus X10⁻⁸/Pa Poisson's ratio Glassythermoplastic^(1,2) 6.9 0.3 semi-crystalline thermoplastic¹ 21 0.4Thermoplastic elastomer² 0.21 0.5 ¹Materials used in the rigid cubecorner films. ²Materials used in the flexible cube corner films

TABLE 1b Laminate constructions, most flexible to most rigid 1 3.8 milglassy thermoplastic film 2 Sealed, most flexible cube corner film 3Vapor coated, semi-flexible cube corner film 4 Vapor coated, rigid cubecorner film 5 Sealed, rigid cube corner filmThe test strips had widths W, lengths L, and were spaced apart by adistance δ. The first observation was that if the distance between thesegment ends was too small, the ends butted up against each other orslide one on top of the other as the canvas was flexed. It appeared thatthe smallest δ that kept the ends from butting was approximately:

$\begin{matrix}{\delta_{\min} \approx {( \frac{t/2}{R} ) \times L}} & {{Equation}\mspace{14mu} 1}\end{matrix}$where t was the laminate thickness. (The term in brackets is the strainat the first major surface of the segment.) The equations below providefurther details of this term.

The second observation was that, longer segment lengths failed at largerradii than shorter segments while for a given segment length, a morerigid segment would fail at smaller radius than a less rigid segment.Using shorter lengths, more rigidity, or limiting the radius above acertain size all served to attenuate the likelihood of this wrinklefailure mode. Table 2 list minimum lengths that were observed to avoidthis failure mode for segments of the five test laminate constructionsbent around a 6.4 mm radius.

TABLE 2 Laminate constructions, most flexible minimum length to to mostrigid avoid wrinkles 1 3.8 mil glassy thermoplastic film 51 mm 2 Sealed,most flexible cube corner film 51 mm 3 Vapor coated, semi-flexible cubecorner film 64 mm 4 Vapor coated, rigid cube corner film 64 mm 5 Sealed,rigid cube corner film 83 mm

The following derivations are useful for analytically predicting segmentfailure by wrinkling. The derivations apply strictly to elasticmaterials. Laminates are assumed to be made up of isotropic laminae.Applied loads, deformations, and reactions are illustrated in onedimension only. When an initially flat laminate bends along one axisinto a radius, R, the surface to the inside of the cylinder formedcompresses while the outside surface is placed in tension. For a segmentthat might be made of a single layer of material (e.g. laminateconstruction #1) the plane midway between the surfaces is neutral sinceit is in neither compression nor tension. The strains, δ, at thesurfaces of the layer are as follows:

$\begin{matrix}{{ɛ = {\frac{t/2}{R}\mspace{14mu}{for}\mspace{14mu}{an}\mspace{14mu}{initially}\mspace{14mu}{flat}\mspace{14mu}{single}\mspace{14mu}{layer}}},} & {{Equation}\mspace{14mu} 2a}\end{matrix}$

Retroreflective sheetings are laminates where the neutral axis is a morecomplex function of the position in and moduli of the materials thatmake up the laminate. For the case of a laminate, the numerator of EQN.2a is the distance, y_(n), of the first major surface to the neutralaxis. The plane of the neutral axis, like the mid-plane of the singlelayer, is in neither compression nor tension when the laminate isflexed. In such case, the first major surface reacts with the strainexpressed in EQN. 2b:

$\begin{matrix}{{ɛ = {\frac{y_{n}}{R}\mspace{14mu}{for}\mspace{14mu}{an}\mspace{14mu}{initially}\mspace{14mu}{flat}\mspace{14mu}{laminate}}},} & {{Equation}\mspace{14mu} 2b}\end{matrix}$

The total compressive stress on the laminate, P_(comp), can be foundusing EQN. 3.P _(comp) =ε×A,  Equation 3where A is the extensional stiffness of the laminate. For a segment ofone material layer,

$\begin{matrix}{A = {( \frac{Et}{( {1 - v^{2}} )} ).}} & {{Equation}\mspace{20mu} 4a}\end{matrix}$where E is the modulus, and ν is Poisson's ratio. For the case of alaminate comprised of ‘N’ laminae, as we discuss here, A is calculatedas the sum of modulus of the individual laminae weighted by itsrespective thickness, where i denotes the i-th lamina. For the laminacontaining the first major surface, i=1. E_(i), t_(i), and v_(i) are themodulus, thickness, and Poisson's ratio respectively, of the i-thlamina.

$\begin{matrix}{{A = {\sum\limits_{i = 1}^{N}\frac{E_{i}t_{i}}{( {1 - v_{i}^{2}} )}}},} & {{Equation}\mspace{14mu} 4b}\end{matrix}$The neutral axis is located a depth y_(n) from the first major surfaceof the laminate where one can calculate y_(n) from EQN. 4c.

$\begin{matrix}{{y_{n} = {\frac{1}{2}\frac{\sum\limits_{i = 1}^{N}\{ {\frac{E_{i}}{( {1 - v_{i}^{2}} )}\lbrack {( {\sum\limits_{j = 1}^{i}t_{j}} )^{2} - ( {\sum\limits_{k = 0}^{i - 1}t_{k}} )^{2}} \rbrack} \}}{\sum\limits_{i = 1}^{N}\frac{E_{i}t_{i}}{( {1 - v_{i}^{2}} )}}}},{{{where}\mspace{20mu} t_{0}} = 0.}} & {{Equation}\mspace{14mu} 4c}\end{matrix}$The units of P_(comp) and A are in force per length. A segment whethercomprised of a single layer or a laminate will flex without wrinkling ifP_(comp) is below a critical threshold, P_(cr). If P_(comp) is greaterthan P_(cr), then the segment wrinkles in response to the compressiveload. The critical threshold, P_(cr) is a proportional to the ratio ofthe bending rigidity of the segment to the square of its length or:

$\begin{matrix}{P_{cr} \equiv {k{\frac{D}{L^{2}}.}}} & {{Equation}\mspace{14mu} 5}\end{matrix}$D is the bending rigidity of the retroreflective laminate. For a singlelayer segment,

$\begin{matrix}{{D = \frac{{EI}/W}{( {1 - v^{2}} )}},} & {{Equation}\mspace{20mu} 6a}\end{matrix}$where I is the moment of inertia for the layer, I=t³W/12. For the caseof a laminate D is calculated as the sum over all laminae of the productof modulus of the individual laminae to the cube of the distance thatlaminae is from the neutral axis. A straightforward algorithm tocalculate rigidity is:

$\begin{matrix}{{D = {\frac{1}{3}{\sum\limits_{i = 1}^{N}{\frac{E_{i}}{( {1 - v_{i}^{2}} )}{( {z_{i}^{3} - z_{i + 1}^{3}} ).}}}}},} & {{Equation}\mspace{20mu} 6b}\end{matrix}$where z_(i) is the distance from mid-plane of the laminate to theinterface between the i-th and (i-th+1) laminae. For example: z₀ is thedistance from the mid-plane to the first major surface; z_(N) is thedistance from the mid-plane to the second major surface. Note, z₀–z₁equals t₁, z₁–z₂=t₁ and so on; z₀–z_(N) is the thickness of thelaminate.

The proportionality, k, between the left side and right side of EQN. 5depends on edge constraints, and other factors that add complexity. Wederive an empirical relationship based on experiments with the fivelaminate constructions. Combining EQNS. 2 and 3 and setting EQN. 5, thecritical compressive load, to less than EQN. 2, the compressive load ofthe bent segment, yields an expression that defines the longest segmentlength that avoids wrinkle failure.

$\begin{matrix}{L_{\max} \leq {\lbrack {{k( \frac{D}{A} )}( \frac{R}{y_{n}} )} \rbrack^{1/2}.}} & {{Equation}\mspace{14mu} 7}\end{matrix}$For the case of a single lamina (D/A)=t²/12, y_(n)=(t/2), and EQN. 7reduces to:

$\begin{matrix}{{L_{\max} \leq \lbrack {k\frac{t^{2}R}{12( \frac{t}{2} )}} \rbrack^{1/2}} = {\lbrack {( \frac{k}{6} ){Rt}} \rbrack^{1/2} = {\lbrack {k^{\prime}{Rt}} \rbrack^{1/2}.}}} & {{Equation}\mspace{14mu} 8}\end{matrix}$

When the laminae of a laminate are composed of materials with similarmoduli, the simpler EQN. 8 is essentially identical to the more rigorousEQN. 7. In what follows we will use the more rigorous EQN. 7. Table 3lists the laminate properties of the constructions first shown in Table2.

TABLE 3 Stiffness* 10⁻⁴ Rigidity* 10⁴ Neutral axis, Construction A/(N/m)D/(N*m) y_(n)/mm 1 3.8 mil glassy thermoplastic film 0.97 0.76 0.048 2Sealed, most flexible cube corner film 1.1 1.8 0.12 3 Vapor coated,semi-flexible cube corner film 1.5 5.4 0.13 4 Vapor coated, rigid cubecorner film 2.3 9.8 0.13 5 Sealed, rigid cube corner film 2.6 24 0.20

Table 4, shown below, combines the results listed first in Table 2 andthe values calculated as suggested from EQN. 7.

TABLE 4 Minimum length/mm to (D/A*(R/y_(n)))^(1/2)/mm Construction avoidwrinkles, L_(min) R = 6.4 mm 1 51 0.33 2 51 0.30 3 64 0.43 4 64 0.46 583 0.56

FIG. 9 shows a plot of (D/A*(R/y_(n)))^(1/2) vs. L_(min) for laminatesof the study adhered to the test canvas substrate and bent around amandrel having a radius of 6.4 mm. A linear regression fit is shown, aswell as the equation and R² values. Using the regression fit shown inFIG. 9, a generalization about the minimum segment length that avoidsthe compression-wrinkling failure for a laminate-segment of specificstiffness and rigidity if forced to bend when a canvas is flexed can nowbe made. Specifically, where the conditions of EQN. 11 are met,wrinkling is generally avoided.

$\begin{matrix}{{L_{\min}\text{/}{mm}} \leq {{120( \frac{D}{A} )^{1/2}( \frac{R}{y_{n}} )^{1/2}} + 12}} & {{Equation}\mspace{11mu} 11} \\{R^{2} = 0.95} & \;\end{matrix}$

The properties of the article relate to the final article, i.e., thearticle as used on the substrate. For example, if the carrier is meantto be removed from the final article as used on the substrate, then thecarrier is not included in the calculations for the article.

The present invention has now been described with reference to severalembodiments thereof. The foregoing detailed description and exampleshave been given for clarity of understanding only; no unnecessarylimitations are to be understood therefrom. It will be apparent to thoseskilled in the art that many changes can be made in the embodimentsdescribed without departing from the scope and spirit of this invention.Thus, the scope of the present invention should not be limited to theexact details and structures described herein, but rather by thestructures described by the, language of the claims, and the equivalentsof those structures.

For use on vehicles having flexible sides (e.g., canvas-sided truck), ithas been found that preferred sheeting segments have a length sufficientto accommodate any required homologation marking, more preferably have alength of at least 12 mm, most preferably at least 24 mm and optimallyat least 48 mm. A suitable sheeting segment may be up to several feetlong, if desired. Sheeting width is typically between about 30 mm andabout 120 mm, more preferably between about 40 and about 100 mm. The gapsize between adjacent segments may be regulated by a governmental body.Often the preferred gap size is that which meets the applicableregulation. For example, in the United States a preferred gap size isequal to the length of the shortest adjacent segment. In Europe, the gapsize is preferably equal to one-half the length of the shortest adjacentsegment.

Notwithstanding the above regulations, on canvas substrates the segmentsize and gap size are preferably chosen based upon the physicalproperties of the substrate. Free bending is facilitated when thesheeting segments are shorter. Also, the preferred gap size is somewhatdependant on the thickness of the substrate, with preferred minimum gapsize being at least 2–4 times the thickness of the substrate. For atypical 50 mm long segment on a 0.53 mm thick canvas truck-side, the gapsize is preferably at least about 4 mm. Larger gaps may be utilized, ifdesired.

The articles of the present invention can be made in a variety of ways.One preferred method comprises the steps of: (1) providing an elongatestrip of a carrier having a first major surface and a second majorsurface; (2) providing an elongate strip of a retroreflective sheeting,wherein the sheeting has a first major viewing surface and a secondmajor opposing surface (preferably an adhesive surface); (3) cutting thestrip of retroreflective sheeting into discrete segments; and (4)attaching the first major viewing surface of the sheeting to the secondmajor surface of the carrier. If desired more than one type of sheetingcan be attached to the carrier. This may be done, for example, bysequentially attaching segments of a first sheeting type along thecarrier and attaching segments of a second or subsequent type ofsheeting in gaps between the first type of sheeting.

It may be desirable to rotate a sheeting segment prior to attaching itto the carrier. This may be done, for example, to conserve material. Adiamond pattern can be cut with minimal waste from a strip of sheetingwhen cut as rectangles and then rotated 45 degrees. Also, a sheetinghaving a particular angularity (e.g., leftward) can be cut into squaresand rotated 90 degrees, 180 degrees and 270 degrees to provide upward,rightward and downward angularity.

In another process a strip of sheeting can be provided on a stretchableliner, “kiss-cut” through the sheeting to the depth of the liner to forma plurality of segments on the liner; and stretched in one or moredirections (e.g., lengthwise or widthwise, etc.) to separate thesegments. A carrier can then be laminated to the separated segments (andthe liner optionally removed) to provide a segmented sheeting article.This method generally includes the steps of: providing an elongate stripof a retroreflective sheeting on a release liner, wherein the sheetinghas a first major viewing surface and a second major opposing adhesivesurface protected by the liner; cutting (e.g., “kiss-cutting”) theelongate strip of retroreflective sheeting into smaller discretesegments on the liner; stretching the liner in at least one direction(e.g., lengthwise or widthwise, etc.) to separate segments; andattaching, preferably “removably” attaching, the first major viewingsurface of the sheeting to a second major surface of an elongate stripof a carrier having a first major surface and the second major surface

In another process a strip of sheeting can be provided on a liner,“kiss-cut” to the depth of the liner to form a plurality of segments onthe liner; and pieces of the sheeting removed to separate the remainingsegments. A carrier can then be laminated to the separated segments (andthe liner optionally removed) to provide a segmented sheeting article.In the event that the removed sheeting is not reused or reusable, thisprocess is presently less preferred due to the resultant waste of theremoved sheeting. This method generally includes the steps of: providingan elongate strip of a retroreflective sheeting on a release liner,wherein the sheeting has a first major viewing surface and a secondmajor opposing adhesive surface protected by the liner; cutting (e.g.,“kiss-cutting”) the elongate strip of retroreflective sheeting intosmaller discrete segments on the liner; removing selected portions ofthe sheeting to separate the remaining segments; and attaching the firstmajor viewing surface of the sheeting to the second major surface of anelongate strip of a carrier having a first major surface and a secondmajor surface.

Several methods may be employed when applying the retroreflectiveconspicuity article to a vehicle. One preferred process involves thesteps of: (1) providing an elongate strip of a conspicuity articlehaving a carrier having a first major surface and a second major surfaceand a plurality of discrete segments of a retroreflective sheeting,wherein the sheeting has a first major viewing surface and a secondmajor opposing adhesive surface, and wherein the first major viewingsurface of the sheeting is removably attached to the second majorsurface of the carrier; (2) exposing the second major opposing adhesivesurface of the sheeting; (3) applying the adhesive surface of thesheeting to a surface of a vehicle to thereby adhere the sheeting to thevehicle. The applying step may optionally include the step of stretchingthe carrier to position the sheeting segments in desired position (e.g.,around a corner, over a fold line in a canvas truck siding, over arivet, etc.). Gaps in the article may also be shortened, when desired,by simply pushing the segments closer together.

In preferred embodiments the carrier is then removed to expose theviewing surface of the sheeting. This may be done, for example, bypeeling the carrier off.

If desired, the above process may be performed multiple times along asubstrate, e.g., to cause more than one type of sheeting to be adheredto the substrate. For example, a first application can provide asegmented article to be applied having large gaps between segments. Asecond application of a segmented article can be performed along thesame line, thereby placing a second sheeting in a portion of the gaps.

A further advantage of the segmented articles of the present inventionis that damaged segments may be easily repaired or replaced withouthaving to cut the applied article.

The following examples are offered to aid in understanding of thepresent invention and are not to be construed as limiting the scopethereof These examples are offered to further illustrate the variousspecific and preferred embodiments and techniques and to further explaincertain features and advantages. It should be understood, however, thatmany variations and modifications may be made while remaining within thescope of the present invention. Unless otherwise indicated, all partsand percentages are by weight.

EXAMPLES Example 1 Conspicuity Articles

-   (A) The following retroreflective sheeting materials were cut to the    size and shape noted and used to construct various conspicuity    articles:    -   (A1) 3M #970 retroreflective sheeting—55 mm×55 mm square        segments.    -   (A2) 3M #983 retroreflective sheeting—55 mm×55 mm'square        segments.    -   (A3) 3M #981 retroreflective sheeting—55 mm×55 mm square        segments.    -   (A4) 3M #981 retroreflective sheeting—14 mm×55 mm rectangular        segments.    -   (A5) Sheeting available from Reflexite Corporation of Avon,        Conn. sold under the trade designation “VC 104 Patt WH Curtain        Grade Sheeting.” Metalized, 50 mm×50 mm square segments.    -   (A6) Sheeting available from Stimsonite Corporation of        Parsippany, N.J. sold under the trade designation “4500        Sheeting.” Metalized 52 mm×52 mm square segments.-   (B) As a test substrate the following canvas was used:    -   (B1) Verseidag Indutex/German, type Duraskin 12 B129835, Color        #070 blue. The thickness of this canvas was about 0.53 mm.-   (C) The following materials were used as an illustrative carriers:    -   (C1) 3M product # TPM-5 ECF film. This is a polyethylene film        with a low tack adhesive on one side and a silicone release        coating on the opposite side. The thickness of this material is        about 0.14 mm.    -   (C2) 3M polyethylene Type 3112 tape. This is a low density        polyethylene with low-tack adhesive on one side and a thickness        of about 0.08 mm.-   (D) The following material was used as an illustrative release    liner:    -   (D1) A Co-poly release liner film (about 0.085 mm thick) that        comprises a propylene copolymer and is coated with a silicone        polymer. Suitable liners are commercially provided with the        aforementioned 3M #981 sheeting.

Example 1 Run 1

A conspicuity sheeting article was constructed according to FIG. 2 a,wherein carrier 16 comprises the aforementioned carrier (C1) having awidth equal to sheeting 12; sheeting 12 comprises 3M #981retroreflective sheeting—55 mm×55 mm square segments; and liner 24 acomprises the aforementioned liner (D1). Gaps between segments werebetween about 20 and 30 mm. In one embodiment alternating segments wererotated 90 degrees to give a tiling effect.

Example 1 Run 2

A conspicuity sheeting article was constructed according to FIG. 2 a,wherein carrier 16 comprises the aforementioned carrier (C1) having awidth equal to sheeting 12; sheeting 12 comprises 3M #970retroreflective sheeting—55 mm×55 mm square segments; and liner 24 acomprises the aforementioned liner (D1). Gaps between segments werebetween about 20 and 30 mm.

Example 1 Run 3

A conspicuity sheeting article was constructed according to FIG. 2 a,wherein carrier 16 comprises the aforementioned carrier (C1) having awidth equal to sheeting 12; sheeting 12 comprises 3M #983retroreflective sheeting—55 mm×55 mm square segments; and liner 24 acomprises the aforementioned liner (D1). Gaps between segments werebetween about 20 and 30 mm.

Example 1 Run 4

A conspicuity sheeting article was constructed according to FIG. 2 a,wherein carrier 16 comprises the aforementioned carrier (C1) having awidth equal to sheeting 12; sheeting 12 comprises Reflexite, VC 104 PattWH Curtain Grade Sheeting. Metallized, 50 mm×50 mm square segments; andliner 24 a comprises the aforementioned liner (D1). Gaps betweensegments were between about 20 and 30 mm.

Example 1 Run 5

A conspicuity sheeting article was constructed according to FIG. 2 a,wherein carrier 16 comprises the aforementioned carrier (C1) having awidth equal to sheeting 12; sheeting 12 comprises Stimsonite, 4500Sheeting. Metallized 52 mm×52 mm square segments; and liner 24 acomprises the aforementioned liner (D1). Gaps between segments werebetween about 20 and 30 mm.

Example 1 Run 6

A conspicuity sheeting article was constructed according to FIG. 7 a,wherein carrier 16 comprises the aforementioned carrier (C1) having a 65mm width; sheeting 12 comprises 3M #983 retroreflective sheeting—55mm×55 mm square segments; and liner 24 a comprises the aforementionedliner (D1). Gaps between segments were between about 20 and 30 mm. Inthis embodiment carrier extends past the sheeting segments and providesadditional adhesion to a substrate.

Example 1 Run 7

A conspicuity sheeting article is constructed according to FIG. 2 a,wherein carrier 16 comprises the aforementioned carrier (C1) having awidth of 55 mm; sheeting 12 comprises 3M #981 retroreflectivesheeting—14 mm×55 mm rectangular segments; and liner 24 a comprises theaforementioned liner (D1). Gaps between segments are suitably betweenabout 4 and 7 mm.

Example 1 Run 8

A conspicuity sheeting article was constructed according to FIG. 2 a,wherein carrier 16 comprises the aforementioned carrier (C1) having awidth equal to sheeting 12; sheeting 12 comprises 3M #981retroreflective sheeting—55 mm×55 mm square segments (cut to provide redor white color segments); and liner 24 a comprises the aforementionedliner (D1). Gaps between segments were between about 20 and 30 mm andalternating segments were colored either red or white.

Example 1 Run 9

A conspicuity sheeting article was constructed according to FIG. 2 a,wherein carrier 16 comprises the aforementioned carrier (C2) having awidth equal to sheeting 12; sheeting 12 comprises 3M #981retroreflective sheeting—55 mm×55 mm square segments; and liner 24 acomprises the aforementioned liner (D1). Gaps between segments werebetween about 20 and 30 mm. In one embodiment alternating segments wererotated 90 degrees to give a tiling effect.

The present invention has now been described with reference to severalembodiments thereof. The foregoing detailed description and exampleshave been given for clarity of understanding only; no unnecessarylimitations are to be understood therefrom. It will be apparent to thoseskilled in the art that many changes can be made in the embodimentsdescribed without departing from the scope and spirit of this invention.Thus, the scope of the present invention should not be limited to theexact details and structures described herein, but rather by thestructures described by the language of the claims, and the equivalentsof those structures.

Unless otherwise indicated herein or during examination, for purposes ofboth examination and construction of the appended claims: a claimwritten in a “Product-by-process” format shall be examined and construedas not being limited to products prepared by the particular process setforth in the claim; a claim that uses the term “means for” shall beexamined and construed as being within the meaning of section 112(6);and claims that do not use the term “means for” shall be examined andconstrued as not being within the meaning of section 112(6); and thesteps of a method claim may be performed in any order and are not to belimited to the order presented.

The section headings in this document are inserted for convenience onlyand shall not constitute a part hereof. The present invention may besuitably practiced in the absence of any element not specificallydescribed above.

1. A method of applying a retroreflective article comprising a pluralityof discrete segments of retroreflective sheeting to a flexiblesubstrate, comprising the steps of: providing an elongate strip of anarticle having (i) a carrier with a first major surface and a secondmajor surface and (ii) the plurality of discrete segments ofretroreflective sheeting having a first major viewing surface and asecond major opposing adhesive surface protected by a release surface,wherein the first major viewing surface of the discrete segments ofretroreflective sheeting is attached to the second major surface of thecarrier; exposing the second major opposing adhesive surface of thesheeting; applying the adhesive surface of the plurality of discretesegments of retroreflective sheeting to the flexible substrate tothereby adhere the plurality of discrete segments of retroreflectivesheeting to the substrate, the discrete segments of retroreflectivesheeting being spaced apart from one another on the flexible substrate adistance sufficient to prevent contact between adjacent segments whenthe substrate is bent a predetermined distance; and further comprisingpartially tearing the carrier along a plurality of discontinuitiesduring the step of applying the adhesive surface of the sheeting to theflexible substrate.
 2. The method of claim 1, wherein exposing thesecond major surface of the plurality of discrete segments ofretroreflective sheeting comprises unrolling a roll containing theplurality of discrete segments of retroreflective sheeting.
 3. Themethod of claim 1, wherein the exposing the second major surfacecomprises removing a release liner prior to applying the retroreflectivearticle.
 4. The method of claim 1, further comprising the additionalstep of: removing the carrier from the applied article to thereby exposethe first major viewing surface of the sheeting.
 5. The method of claim4, wherein the carrier is extensible and permits the article to bepositioned along an irregular surface of a substrate or along a curvedpath.
 6. A method of applying a retroreflective article to a flexiblesubstrate, comprising the steps of: providing an elongate strip of aconspicuity article having an extensional stiffness, A, a bendingrigidity, D, and a neutral axis a distance Y_(n) from a first majorsurface of the final article, and adapted for attachment to a flexiblesubstrate having an anticipated bend radius (r), the conspicuity articlehaving (i) a carrier wit a first major surface and a second majoropposing adhesive surface, wherein the first major viewing surface ofthe sheeting is attached to the second major surface of the, and whereinI is selected based upon calculating$\sqrt{( \frac{D}{A} )( \frac{r}{y_{n}} )};$exposing the second major opposing adhesive surface of the sheeting; andapplying the adhesive surface of the sheeting to the flexible substrate.7. The method of claim 6, wherein the adhesive comprises a hot meltadhesive.
 8. A method of applying a retroreflective article to asubstrate, comprising the steps of: providing an elongate strip of aconspicuity article having (i) an extensible carrier with a first majorsurface and a second major surface and (ii) a plurality of discretesegments of a retroreflective sheeting having a first major viewingsurface and a second major opposing adhesive surface including atackifier and being protected by a release surface, wherein the firstmajor viewing surface of the sheeting is attached to the second majorsurface of the crier and wherein the segments are spaced apart from oneanother to prevent the contact between one another when the article isbent a predetermined amount; exposing the second major opposing adhesivesurface of the sheeting; and applying the adhesive surface of thesheeting to the substrate while stretching the carrier to directapplication of the segments upon the substrate.
 9. A method of applyinga retroreflective article to a flexible substrate, comprising the stepsof: providing an article having a neutral axis a distance y_(n) from afirst major surface of the final article, and adapted for attachment toa flexible substrate having an anticipated bend radius (r), the articlehaving (i) a carrier with a first major release surface and a secondmajor surface and (ii) a plurality of discrete segments of aretroreflective sheeting of length 1 spaced apart from one another by adistance at least ${\frac{y_{n}}{r} \times l},$ the segments having afirst major viewing surface and a second major opposing adhesivesurface, wherein the first major viewing surface of the sheeting isattached to the second major surface of the carrier and (iii) thearticle being provided in a roll so that the second major adhesivesurface of the sheeting is adjacent the first major release surface ofan adjacent layer of the carrier in the roll; exposing the second majoropposing adhesive surface of the sheeting; and applying the adhesivesurface of the sheeting to the flexible substrate to thereby adhere thesheeting to the substrate.
 10. The method claim 9, wherein exposing thesecond major surface comprises unrolling the roll.
 11. The method ofclaim 9, further comprising the additional step of: removing the carrierfrom the applied article to thereby expose the first major viewingsurface of the sheeting.
 12. The method of claim 9, wherein the carrieris extensible and permits the article to be positioned along anirregular surface of a substrate or along a curved path.
 13. The methodof claim 9, wherein the second major surface of the carrier comprises anadhesive, the first major viewing surface of the sheeting is attached tothe second major surface of the carrier with a second adhesion force,the sheeting provides a first adhesion force when attached to asubstrate, and the first adhesion force is greater than the secondadhesion force.
 14. The method of claim 9, wherein the sheeting isselected from the group consisting of enclosed lens beaded sheeting,encapsulated beaded sheeting, prismatic sheeting and combinationsthereof.